The described embodiments relate to a fluid pump, and more particularly, to a fluid pump for use in a thermal system with a boiler and a heat engine.
Is it known in thermodynamics that a heat engine requires the circulation of the working fluid from a cold sink or engine exhaust to a hot source such as a boiler. Fluid pumps are used for this purpose.
As is also well-known in the field, the Rankine Cycle usually used in such thermal systems requires a phase change to pass the working fluid from the low pressure level of the sink or engine exhaust to the high pressure level of the boiler. In other words, the low pressure vapor of the working fluid must be cooled to a liquid before it is pumped back into the high pressure level of the boiler for recycling. During the Rankine Cycle, the semi-saturated low pressure vapor after the engine exhaust must then be cooled using a condenser coil so that the vapor can change phase to the liquid state. The cooled liquid is subsequently pumped back into the high pressure boiler to be reheated again to the vapor state, thus requiring a phase change back from liquid to vapor. A great deal of additional heat input is required to reheat and re-vaporize this liquid to a vapor, causing a great deal of loss in the cycle's thermal efficiency.